How to use my BBM account in another BlackBerry?

Normally when I go from one BlackBerry to another BlackBerry phone and start using bbm, I get a promp how my bbm is associated with another device and if I would like to switch it now. So it's not asking anymore. Bbm shows up fine, I can send messages and even get the D in blue showing up. Yet they don't actually deliver and I don't get any messages. How do I force bbm to promp to switch devices?

That doesn't seem to affect BBM. I tried using a 4th device (Windows Phone) and installed BBM there to force it to sign me off from my Priv, Z30, and Classic. The Priv immediately asked me if I wanted to switch devices but there's no blue 'D'when I send messages; just a checkmark with a green background.